Shock resistance is a sensitive issue for the majority of timepiece oscillators and in particular for resonators with crossed blades. In fact, in the case of out-of-plane shocks the stress undergone by the blades rapidly reaches very significant values, which accordingly reduces the path that the part can travel before yielding.
Shock absorbers for timepieces come in a numerous variants. However, their purpose is primarily to protect the fragile pivots of the shaft and not the elastic elements such as classically the spiral spring.
Document EP3054357A1 in the name of ETA Manufacture Horlogère Suisse SA describes a timepiece oscillator comprising a structure and distinct primary resonators that are temporally and geometrically phase shifted, each having a mass restored to the structure by an elastic restoring means. This oscillator comprises coupling means for interaction of the primary resonators comprising driving means to drive movement of a wheel train, which comprises drive and guide means arranged to drive and guide an articulated control means with transmission means, each articulated, at a distance from the control means with a mass of a primary resonator. The primary resonators and the wheel train are arranged so that the axes of the articulations of any two of the primary resonators and the articulation axis of the control means are never coplanar.
Document EP3035127A1 in the name of SWATCH GROUP RESEARCH & DEVELOPMENT Ltd describes a timepiece oscillator comprising a resonator formed by a tuning fork, which comprises at least two movable oscillating parts fixed to a connecting element by flexible elements, the geometry of which determines a virtual pivot axis of determined position in relation to a plate and around which the respective movable part oscillates, the centre of mass of which is merged in resting position with the respective virtual pivot axis.
For at least one movable part the flexible elements are formed from crossed elastic blades spaced from one another in two parallel planes, the projections of the directions of which on one of the parallel planes cross at the level of the virtual pivot axis of the movable part.